Method of assembling a mask with a frame assembly for mounting in a cathode-ray tube using a remote assembly position

ABSTRACT

The method includes locating three frame-positioning points on a faceplate panel and measuring the panel contour at at least four spaced points on a circle of given radius at a first spacing with respect to the frame-positioning points. Then, at a remote location, (a) a frame assembly is oriented on three reconstructed frame-positioning points which are in substantially the same geometric relationship with respect to one another as are the frame-positioning points on the faceplate panel, (b) signals are generated related to the position of the measured contour of the panel, and (c) the signals are utilized to position four mask supports in substantially the same geometric relationship with respect to one another as are the measured contour points but at a second spacing with respect to the reconstructed framepositioning points. Then, the contour of the mask is conformed to the contour established by the mask supports. With the mask conformed to the contour of the mask supports, the mask is permanently attached to the frame. A particular embodiment of the method also includes measuring the contour of the faceplate panel substantially at the center of the panel, measuring the contour of the mask substantially at the center of the mask and adjusting the second spacing to obtain a desired center spacing between the mask and panel when the mask is mounted in the panel while maintaining the mask conformed to the contour established by the mask supports.

United States Patent Renssen 51 Oct. 31, 1972 [54] METHOD OF ASSEMBLINGA MASK [57] ABSTRACT WITH A FRAME ASSEMBLY FOR The method includeslocating three frame-positioning MOUNTING IN A CATHODE'RAY points on afaceplate panel and measuring the panel TUBE USING A REMOTE ASSEMBLYcontour at at least four spaced points on a circle of POSITION givenradius at a first spacing with respect to the [72] Inventor; Mal-inns vRenssen, Lane'aster, frame-positioning points. Then, at a remotelocation,

p (a) a frame assembly is oriented on three reconstructedframe-positioning points which are in sub- [73] Asslgnee: RCA Corponmonstantially the same geometric relationship with respect 2 Filed; Jam 13,1971 to one another as are the frame-positioning points on the faceplatepanel, (b) signals are generated related Appl' 107,053 to the positionof the measured contour of the panel, and (c) the signals are utilizedto position four mask [52] us. 01 ..29/2s.1s, 29/2513 pp insubstantially the Same geemetrie relation- [51 Int. Cl. ..H01j 9/18, H01j 9/36 p with respect to one another as are the measured [58] Field atSearch ..29/25.1, 25.11, 25.13, 25.15; contour points but at a secondSpacing with respect to 73/375 the reconstructed frame-positioningpoints. Then, the contour of the mask is conformed to the contour [56]References Cited established by the mask supports. With the maskconformed to the contour of the mask supports, the mask UNITED STATESPATENTS is permanently attached to the frame.

MOI'rell A particular embodiment of the method also includes Albertsonet a]. measuring the contour of the faceplate pane] ubstan- 3,482,28612/ 1969 F asssett et al. 29/25.13 tiahy at the center f the panel,measuring the contour 3,537,159 1 1/ 1970 Gartner et a1 "29/2515 X ofthe mask substantially at the center of the mask and 3,537,161 1 H1970Kautz ..29/25.l5 adjusting the second Spacing to obtain a desired center3,564,195 2/1971 Ploog ..29l25.l5 Spacing between the mask and panelwhen the mask is I mounted in the panel while maintaining the mask con-Examme' R bert Baldwm formed to the contour established by the mask sup-Assistant Examiner-Richard Bernard Lazarus ports. Attorney-Glenn H.Bruestle 2 Claims, 5 Drawing Figures i. m i k 12h.

32 Z7e /'Z7d Z8 33& 4/ if 40 mummmfinmnmu METHOD OF ASSEMBLING A MASKWITH A FRAME ASSEMBLY FOR MOUNTING IN A CATHODE-RAY TUBE USING A REMOTEASSEMBLY POSITION BACKGROUND OF THE INVENTION This invention relates toa method of assembling a shadow mask with a frame assembly for mountingin a cathode-ray tube and particularly in a rectangular color-televisionpicture tube using a remote assembly position.

Commercial rectangular shadow-mask-type picture tubes forcolor-television receivers include a curved faceplate panel having, onits inner surface, a mosaic viewing screen of differently emissivephosphor dots and an electron gun structure to project plural electronbeams towards the screen. A domed shadow mask is nested in the faceplatepanel with a prescribed spacing from center to edge such as described inUS. Pat. No. 3,109,116 to D. W. Epstein et al. In the operation of thetube, the electron beams pass through apertures in the mask toselectively excite the phosphor dots.

In one commercial method for assembling a rectangular shaped shadow maskwith a frame assembly prior to mounting in a cathode-ray tube panel, aplurality of spacers is positioned to contact the inner contour of thepanel, a frame with a mask loosely fitted thereon is located in thepanel on frame-positioning means with the mask in plural contact withthe spacers. Pressure is applied to seat the mask against the spacers toconform the mask contour more closely to that of the panel. Then, withthe pressure still applied, the mask is attached to the frame at aplurality of separated perimetric areas. Then, the pressure is removed,and the spacers are removed. A disadvantage of this method is that theframe assembly must be directly oriented in the panel since mechanicalspacers must contact the panel and the mask. This necessitates theassembly of all components by a single operator and required all theprocessing equipment he compacted into a limited working space. Inaddition, the mechanical spacers are of a fixed length. Thisnecessitates that a predetermined spacing between the panel and mask beused since the fixed-length spacers do not permit optimized matching ofmask and panel contours. The use of fixedlength spacers in which themask is pressed into contact with the spacers also presses the spacersagainst the panel. This may cause scuffs or scratches in the glasspanel.

Also the direct orientation of mask and panel with the mask-frameassembly positioned within the panel and oriented on frame-positioningmeans provides a limited amount of space between the inside of the panelsidewall and the attachment points of the mask to the frame, resultingin the necessity for specialized welding equipment. Welding the mask tothe frame in the panel also may cause weld splash, which may damage thepanel.

In another form of the commercial method, the mask and frame assemblyare positioned one above the other with long spacers between the maskand the panel. Mechanical linkage is used to relate theframe-positioning means to its actual position when oriented in thepanel. In addition to the foregoing disadvantages, the use of mechanicallinkage may result in decreased accuracy in assembling the mask to theframe.

In a more specific form of each of the commercial methods previouslydescribed, the spacers are positioned between the mask and the panelnear the corners and at the center of the panel. After the mask isattached to the frame and the pressure is removed, the mask may maintainthe conformed shape near the corners since it is attached near thecorners, but it may not maintain the conformed shape near the centerwhere the domed shape of the mask may have a tendency to spring back toits former shape. Therefore the use of fixed spacers may not result in adesired custom-spaced mask-panel assembly. In addition, provisions arenot included to optimize the spacing between the center and the cornersof the panel or to select a specific spacing at the center of the panelwhich may be desirable to utilize all masks and panels provided.

SUMMARY OF THE INVENTION The novel method includes locating threeframepositioning points on a faceplate panel and measuring the panelcontour at at least four spaced points on a circle of given radius at afirst spacing with respect to the frame-positioning points. Then, at aremote location, (a) orienting a frame assembly on three reconstructedframe-positioning points in substantially the same geometricrelationship with respect to one another as the frame-positioning pointson the faceplate panel, (b) a signal is generated related to theposition of the measured contour of the panel, and (c) the signal isutilized to position four mask supports in substantially the samegeometric relationship with respect to one another as the measuredcontour points but at a second spacing with respect to the reconstructedframe-positioning points. Then, the contour of the mask is conformed tothe contour established by the mask supports and the mask is permanentlyattached to the frame while the mask is conformed to the contour of themask supports.

Unlike the prior methods, the novel method permits custom assembly of amask and frame in a position displaced from the panel without the use ofmechanical spacers between the panel and the mask. This permitsorienting the panel and measuring the panel contour in a first position,and then assembling a mask and frame, custom tailored to that panel, ina second position remote and at any desired distance from the firstposition. Also, since mechanical linkage is not used between the firstand second position, it is not necessary to maintain any directorientation between these positions. The elimination of the mechanicallinkage permits remote assembly of the mask-frame assembly and providesfor increased accuracy between the assembly and measured positions.Since the novel method does not press spacers against the panel andinstead uses a nontouch sensing means to measure the contour of thepanel, scratching of the glass panel is substantially reduced. Remoteassembly of the mask and frame also permits easier and more economicalattachment of the mask to the frame and eliminates weld splashing intothe panel. Specialized welding equipment to fit into the limited spacebetween the panel sidewall and the mask is not necessary, resulting infurther economy.

A more specific form of the novel method includes also measuring thecontour of the panel substantially at the center of the panel, measuringthe contour of the mask substantially at the center of the mask andadjusting the second spacing to obtain a desired center spacing betweenthe mask and the inner surface of the panel when the mask is mounted onthe panel and conformed to the contour established by the mask supports.

This form of the novel method may be used to provide an optimum spacingbetween the mask and the panel for masks which cannot be sufficientlydistorted to conform to an exact spacing. This results in an economy inthe use of masks and panels which may not otherwise be utilized. Inaddition, this method provides for setting any desired spacing betweenthe mask and the panel at the center of the panel to include setting anexact center spacing. This results in a more uniform viewed image in thefinished tube.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of acolor-television-picturetube panel assembly illustrating the preferredpoints for measurement of spacing.

FIG. 2 is a sectional view of the panel assembly of FIG. 1, on sectionline 22, illustrating the spacing between the faceplate and the maskingmember.

FIG. 3 is a partial sectional view illustrating a first station of anapparatus for practicing the novel method, showing the panel on sectionline 3-3.

FIG. 4 is a partial sectional view illustrating a second station of anapparatus for practicing the novel method, showing the frame assembly onsection line 4-4.

FIG. 5 is a plan view of a color-television-picturetube panel assemblyillustrating additional or alternate points for measurement of spacing.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 and 2 illustrate a panelassembly including a panel 11 and a mask assembly 12 for a rectangularcolor-television picture tube. The panel 11 includes a faceplate 13 anda sidewall 14 having four studs 15a through 15d extending therefrom. Themask assembly 12 includes a mask 16 having a perimetric skirt 17 and aframe assembly 18. The frame assembly 18 comprises a frame 19 having avertically upstanding flange 20 parallel to the skirt 17, four hookplates 21a through 21d attached to the frame 19, and four leaf springs22a through 22d each attached at one end to one of the hook plates 21athrough 21d, and each having a hole 23a through 23d at the other end fordetachably engaging one of the studs 15a through 15d.

The apparatus for practicing the novel method includes a first station24 partially shown in FIG. 3 and a second station 25 partially shown inFIG. 4. The first station 24 includes three stud support member 26athrough 260 (only one of which is shown) and five faceplate-measuringunits 27a through 27e (only three of which are shown) mounted on a firststation frame 28. Two of the stud-support members 26a and 26b (only oneof which is shown in FIG. 3) are positioned in alignment for movement inthe direction of the major axis of the panel 11, and one stud-supportmember 260 (not shown) is positioned for movement perpendicular to thedirection of the two stud-support members 26a and 26b, in the directionof the minor axis of the panel 11. The three stud-support members 26athrough 260 have dummy holes 29a through 290 therein to engage threestuds 15a through 15c respectively (shown in FIG. 1). The dummy holes29a through 29c when engaged with the three studs 15a through define afirst reference plane 30 passing through the longitudinal axes of allthree studs 15a through 15c.

Each faceplate-measuring unit 27a through 27e (only three of which areshown in FIG. 3) comprises a housing 31, a lead screw 32 rotatablymounted in the housing 31 in bearings 33a and 33b, a ball-bearing nut 34engaging the lead screw 32, a guide member 35 attached to the nut 34supported only for axial movement in the housing 31, a sensor-supportmember 36 attached to the guide member 35, a sensing unit 37a through37e (only three of which are shown in FIG. 3) mounted on the sensorsupport member 36, and a drive means 38 for rotating the lead screw 32.The sensing units 37a through 37e are of the proximity-detector type.Since this type sensing unit measures the position of the faceplatewithout contact, a spacing E exists between the end of each of thesensing units 37a through 37e and the inner surface of the faceplate 13.The drive means 38 includes drive motor 39 with motor shaft 40, a drivegear 41 mounted on the motor shaft 40, and a driven gear 42 mounted onone end of the lead screw 32.

The second station 25 shown in FIG. 4 includes three leaf-spring-supportmember 43a through 430 (only one of which is shown in FIG. 4), fourmask-positioning units 44a through 44d (only two of which are shown inFIG. 4) and one mask-measuring unit 45 mounted on a second station frame46. The three leaf-spring-support members 43a through 43c are slidablymounted on the second station frame 46 to correspond to the positioningof the three stud-support members 26a through 260 in the first station24. The three leaf-spring-support members 43a through 43c are formedwith dummy studs 47a through 470 to engage the holes 23a through 23crespectively (shown in FIG. 1) in the leaf springs 22'a through 220(shown in FIG. 1) corresponding in orientation to the position of thethree studs 15a through 150 in the first station 24. The dummy studs 47athrough 47c of the three leaf-spring-support members 43a through 430when engaged with the three leaf springs 22a through 220 (shown inFIG. 1) define a second reference plane 48 passing through thelongitudinal axes of all three holes 23a through 23c (only one of whichis shown in FIG. 4) corresponding to the position of the three studs 15athrough 15c in the first station 24. The second reference plane 48 inthe second station 25 is simulative of and correspond to the firstreference plane 30 in the first station 24.

The four mask-positioning units 44a through 44d (only two of which areshown in FIG. 4) are similar to the five faceplate-measuring units 27athrough 27e except the sensor-support member 36 and the sensing units37a through 37e are replaced with mask-support pins 49a through 49d(only two of which are shown in FIG. 4) which substantially conform tothe inside contour of the mask 16 at the points to be measured. It ispreferred that the ends of each of the mask-support pins 49a through 49dare approximately one-half inch in diameter to provide a support surfaceof sufficient area to prevent denting of the mask 16, and to average acontour surface area on the mask 16 for use as a measurement reference.The mask-measuring unit 45 is similar to the faceplate-measuring unit27e and includes maskesensing unit 50, which is similar tofaceplate-sensing unit 37e. Since the mask-sensing unit 50 is also aproximity-detector type, 2 spacing E exists between the end of thesensing unit 50 and e nner surfaszeofthemask 6.-

The second station 25 also includes welding means (not shown) forattaching the skirt 17 of the mask 16 to the vertical flange on theflame 19, comprising a portable or hand-carried welding unit such as anelectric resistance spot welder. One faceplate-measuring unit 27e andone mask-measuring unit 45 are positioned substantially at the centerpoint 51 of the panel 11. Four faceplate-measuring units 27a through 27dand four mask-positioning units 4411 through 44d respectively arepositioned parallel to the axis of the tube at an equal radial distancefrom the center point 51 along the diagonal lines connecting oppositecorners of the panel 11 and near each of the four corners of the I panel11 at points 52a through 52d as shown in FIG. 1. The points 52a through52d are bisymmetrical with the center point 51. For example, in a VABP22colortelevision picture tube, each of the four corners points 52athrough 52d is on a corner diagonal line at an 8.602-inch radius fromthe center point 51 of the panel 11.

The center point 51 (shown in FIG. 1) of the panel 11 is established bydefinition to be the intersection of a major axis plane established bythe two studs 15a and 15b (shown in FIG. 1) respectively and a minoraxis plane perpendicular to the major axis plane established by one stud15c (shown in FIG. I). Also by definition, the term bisymmetrical asused herein means the panel 11, faceplate 13, and mask 16 are divisibleinto two mirror-image halves by either of the two above-- mentionedintersecting minor and major axis planes passing through the centerpoint 51 of the panel 11.

The first station 24 and the second station 25 are positioned remotefrom each other and connected by electrical controls (not shown). Thedrive motors 39 of each faceplate-measuring unit 27a through 27e andeach correspondingly oriented mask-positioning unit 44a through 44d andmask-measuring unit 45 are electrically connected for synchronizedoperation. Therefore signals from the drive motors 39 in the firststation 24 relating to the position of the sensing units 37a through 372are utilized to operate the drive motors 39 in the second station 25 toposition the four mask-support pins 49a through 49d in substantially thesame geometric relationship as the measured points 52a through 52d.

In the operation of the first station 24 shown in FIG. 3, a panel 11 ispositioned with two exterior reference pads (not shown) on the panelfacing the operator. Then three frame-positioning points comprising thethree studs 15a through 150 are located on the panel 5 11. The threestuds 15a through 150 are located by engagement with the dummy holes 29athrough 29c in the three stud-support members 26a through 26c (only oneof which is shown in FIG. 3) to define the first reference plane 30. Itis preferred to use only three dummy holes 29a through 290 to engagethree panel studs 15a through 150 respectively in the first station 24to establish the first reference plane 30 since this substantiallyresults in establishment of the same first of the number of times thepanel 11 replaced on the apparatus.

The panel contour is then measured at the four points 52a through 52d ata first spacing between the first reference plane 30 defined by thethree framepositioning points and the inner surface of the panel 11. Thefirst spacing between the inner surface of the panel 11 and the firstreference plane 30 at the diagonal points 520 through 52d is designatedspacing B .(shQwain J The panel contour is measured by operating eachfaceplate-sensing unit 37a through 37e. In the operation of eachfaceplate-sensing unit 37a through 37e the drive motor 39 rotates thelead screw 32 through drive gear 41 and driven gear 42 to move the guidemember 35, sensor-support member 36 and faceplate-sensing units 37athrough 37e towards the inner surface of the panel 11. When each of thefaceplate-sensing units 37a through 37e is within a predeterminedspacing E, from the panel 11 inner surface, it senses this surface, anda control circuit stops the drive motor 39 within approximately 0.001inch from the actual position of the inner surface of the panel 11. Themeasurement is complete when each of the five faceplate-sensing units37a through 37e is in proper measurement positions with the innersurface of the panel 11, and each of the drive motors 39 is stopped.Signals are generated from the drive motors 39 which relate to themeasured contour of the panel 11 at the points 52a through 52d and the29m P9i t In the operation of the second station 25 shown in FIG. 4, aframe assembly 18 (shown in FIG. 1) is preassembled with four hookplates 21a through 21d (1 four is removed and 5 leaf springs 22a through22d using the four studs 15a through (shown in FIG. 1) of a particularpanel 11 as a fixture in a well known manner. Once the frame assembly 18is preassembled and identified with a particular panel 11, they arematched work pieces for all further processing including the novelmethod herein aq ibsd The preassembled frame assembly 18 is oriented onthree frame-positioning points in substantially the same geometricrelationship to one another as the panelpositioning points. The threeframe-positioning points comprise three dummy studs 47a through 47cwhich engage the holes 23a through 23c in the three leaf spring supportmembers 43a through 43c (only one of which is shown in FIG. 4) to definethe second reference plane 48. The first reference plane 30 (FIG. 3) andthe second reference plane 48 (FIG. 4) are intended to be coincident andsimulative of the plane (not shown) of the three studs 15a through 15cof an assembled panel 11 where the panel 11 and the frame assembly 18are matched and the matched orientation is maintained during allsubsequent processing steps as ,PI Y .Y .d .b

Then, the signals related to the measured contour of the panel 11 at thepoints 52a through 52d in the first station 24 are utilized to positionfour mask-support pins 49a through 49d in substantially the samegeometric relationship with respect to one another as the measuredcontour of the panel 11 at four measured points 52a through 52drespectively at a second spacing from the second reference plane 48 asdefined by the three frame-positioning points on the studs 15a through150 reference plane 30 for a particular panel 11 regardlessrespectively.

The second spacing between the ends of the four mask-support pins 49athrough 49d in contact with the mask 16 and the second reference plane48 is designated spacing D (shown in FIG. 4). The spacing D isestablished so that the desired spacing q is obtained with the maskassembly 12 assembled in the matching panel 11. The measured spacing qisobtained from the formula:

where qis the measured spacing parallel to the axis of the tube and t isthe thickness of the mask 16. The actual spacing q is then calculatedfrom the measured spacing a and electrical and geometrical parameters ofthe tube in a well known manner. The actual spacing q is defined hereinto be the distance between the inner surface of the panel 11 and mask 16measured normal to the inner surface of the panel 11.

The shadow mask 16 is temporarily supported in the second station 25with the skirt l7 overlapping the vertical flange on the frame 19supported by the four mask-support pins 49a through 49d. The mask 16 isthen flexed or slightly distorted to conform the contour of the mask 16to the contour established by the support pins 49a through 49d. Aclamping means (not shown) is used to maintain the mask substantiallyconformed to the contour of the mask-support pins 49a through 49d duringattachment of the mask 16 to the frame 19.

The mask 16 is then permanently attached to the frame 19 in the secondstation at the established second spacing. It is preferred that theskirt 17 be welded to the flange 20 at a limited number of perimetricpoints to permit movement of the mask 16 during heat up of the tube.

The panel 11 and mask assembly 12 is then removed from the first andsecond stations 24 and 25 respectively and assembled as matched workpiece for further processing. The apparatus resets to a standby positionin preparation for processing subsequent work pieces.

In a more specific form of the novel method, after the mask contour isconformed in the second station 25 to the contour established by thefour support pins 49a through 49d, the first spacing is measured in thefirst station 25 between the first reference plane and the inner surfaceof the panel 11 at a center point 51 of the panel 11. The first spacingbetween the inner surface of the panel 11 and the first reference plane30 at the center point 51 is designated spacing A (shown in FIG. 3). Thesecond spacing between the second reference plane 48 and the innersurface of the mask 16 is measured in the second station 25 at thecenter point 51.

The measured spacing q at the center point 51 designated spacing C(shown in FIG. 4) is determined from the formula:

where qis the spacing parallel to the axis of the tube and t is thethickness of the mask 16. The actual spacing q is then calculated fromthe measured spacing q and the electrical and geometrical parameters ofthe tube.

After the spacing Eat the center point 51 is measured and the actualspacing q is computed, it is compared with the desired spacing q. If theactual spacing q is within the desired spacing q, the mask 16 ispermanently attached to the frame. For example, for a 25VABP22color-television picture tube, the desired spacing q at the center point51 is 0.5540 1- 0.l5 inch, and the desired spacing q at the four points52a through 52d is 0.5080 i 0.015 inch. Therefore, if the actual spacingq at the center point is within the desired spacing q of 0.5540 i 0.015inch, the mask 16 is permanently attached to the frame 19.

If the actual spacing q is greater or less than the desired spacing atthe center point 51, the position of the mask 16 is adjusted withrespect to the second reference plane 4-8. In readjusting the positionof the mask 16, all four mask-positioning units 44a through 44d aresimultaneously operated to raise or lower the four mask-support pins 49athrough 49d while maintaining the mask 16 conformed to the contour ofthe contact pins 490 through 4 9d. If the desired spacing q at thecorners points 52a through 52d is exceeded before a desired spacing q atthe center point 51 is obtained, the mask 16 is not attached to theframe 19. For example, if the desired spacing q of 0.5540 i 0.015 inchat the center point 51 and the desired spacing q of 0.5080 i 0.015 inchat the points 52a through 52d cannot be obtained, the mask 16 is notattached to the frame 19. The first mask is then replaced with asubsequent mask and the process is repeated. When the subsequent maskcannot be adjusted to the predetermined spacing, all work pieces arerejected without assembling. Therefore, masks 16 and frame assemblies 18which cannot be satisfactorily spaced are not assembled, eliminatingfurther uneconomical processing and resulting in the salvage of usablecomponents.

Where the desired spacing q at the center point 51 has a zero tolerance(no tolerance such as the 0.015 inch in the example given) the mask 16is adjusted with respect to the second reference plane 48 until thedesired zero tolerance actual spacing q obtained at the center point 51.If the actual spacing q at the points 52a through 52d is within thedesired spacing q, then the mask 16 is permanently attached to the frame19, and if it is not within the desired spacing q, then the mask 16 andframe 19 are not assembled.

Although it is described that the same spacing is established betweenthe mask 16 and the inner surface of the panel 11 at four points ofequal radius with respect to the center point 51 of the panel 11, it isonly necessary that at least four points on a circle of given radius beselected, and that the points selected be spaced on a given circle. Twosets of two symmetrical points illustrated by points 53a and 53b and 54aand 54b located on the minor axis and minor axis respectively of thepanel 11 on circles of different radius with respect to the center point51 of the panel 11 as shown in FIG. 5 may also be selected. For example,in the 25VABP22 color-television picture tube previously described, theradius of the two points 53a and 53b is 7.000 inches, and the radius ofthe two points 54a and 54b is 9.000 inches. The spacing q at the points53a and 53b is about 0.5282 inch and at the points 54a and 54b is about0.5030 inch. In addition points, such as for example points 55a through55d and 56a through 56d (shown in FIG. 5), may be selected on circles ofdifferent radius other than or in addition to the circle of the points52a through 52d described.

The desired value of spacing q at each position 51, 52a through 52d, 53aand 53b, 54a and 54b, 55a through 55d and 56a through 5611 can becomputed and adjusted to compensate for expansion of the mask 16 duringthe welding operation and for assembly errors so that the desiredspacing q is obtained in the finished panel assembly.

Although specific apparatus is described for comparing the measurementof a panel 11 and mask 16, other suitable apparatus may be used. As forexample, the method of spacing which has been described may be describedin connection with a particular apparatus where the steps may beperformed by hand. In such a case, the panel 11, a preassembled frameassembly 38 and a mask 16 are positioned in fixtures as previouslydescribed in a first and second station remote from each other. Thedistances A, B, C and D are measured by manual-measuring means such asmicrometers or dial gauges, support pins for holding the masking memberare manually moved to establish the desired spacing q, and the mask 16is forced against each support pin to conform the mask 16 to the desiredcontour.

I claim:

1. In the manufacture of a cathode-ray-tube maskpanel assembly includinga rectangularly shaped faceplate panel having a curved faceplate andsidewalls, at least three support studs extending from said sidewalls, aframe assembly including a frame having frame-support members thereonfor engagement with said studs supported in said panel, and an aperturemask positioned on said frame, the method of assembling said mask onsaid frame comprising the steps of a. positioning a panel in a firststation,

b. locating three frame-positioning points on said points on a circle ofgiven radius at a first spacing with respect to said frame-positioningpoints,

(1. generating signals related to said contour at said measured points,

e. then at a second station displaced from said first station and havingno direct physical orientation with said first station establishingthree reconstructed frame-positioning points which are in substantiallythe same geometric relationship with respect to one another as saidframe-positioning points on said panel,

f. then, at said second station utilizing said signals to position fourmask supports in substantially the same geometric relationship withrespect to one another as said measured contour points at a secondspacing with respect to said reconstructed framepositioning points,

g. temporarily positioning a shadow mask on a frame,

h. then, conforming the contour of said mask upon said positioned masksupports, and

i. permanently attaching said mask to said frame while said mask isconformed to said contour of said mask supports.

2. The method of claim 1 including prior to the attachment step, theadditional steps of j. measuring the contour of said panel in said firststation substantially at the center of said panel,

k. measuring the contour of said mask in said second st tio substantiallat the enter of saidm sk, l. adjusting the secoiid spacing between saidmask supports and said reconstructed frame-positioning points to obtaina desired spacing between said mask and said panel when said mask ismounted in said panel while maintaining said mask conformed to saidcontour established by said mask supports.

1. In the manufacture of a cathode-ray-tube mask-panel assemblyincluding a rectangularly shaped faceplate panel having a curvedfaceplate and sidewalls, at least three support studs extending fromsaid sidewalls, a frame assembly including a frame having frame-supportmembers thereon for engagement with said studs supported in said panel,and an aperture mask positioned on said frame, the method of assemblingsaid mask on said frame comprising the steps of a. positioning a panelin a first station, b. locating three frame-positioning points on saidpanel for said tube, c. measuring the contour of said panel at fourspaced points on a circle of given radius at a first spacing withrespect to said frame-positioning points, d. generating signals relatedto said contour at said measured points, e. then at a second stationdisplaced from said first station and having no direct physicalorientation with said first station establishing three reconstructedframe-positioning points which are in substantially the same geometricrelationship with respect to one another as said framepositioning pointson said panel, f. then, at said second station utilizing said signals toposition four mask supports in substantially the same geometricrelationship with respect to one another as said measured contour pointsat a second spacing with respect to said reconstructed frame-positioningpoints, g. temporarily positioning a shadow mask on a frame, h. then,conforming the contour of said mask upon said positioned mask supports,and i. permanently attaching said mask to said frame while said mask isconformed to said contour of said mask supports.
 2. The method of claim1 including prior to the attachment step, the additional steps of j.measuring the contour of said panel in said first station substantiallyat the center of said panel, k. measuring the contour of said mask insaid second station substantially at the center of said mask, l.adjusting the second spacing between said mask supports and saidreconstructed frame-positioning points to obtain a desired spacingbetween said mask and said panel when said mask is mounted in said panelwhile maintaining said mask conformed to said contour established bysaid mask supports.